TL;DR Summon a morbillion level 4 and 8 monsters, draw 10 cards in one turn, discard them all, and win(?). Also you'll brick like 1/10 hands so be ready for that.
I know this deck look wack, but here's some pointers after many hours of playtesting on both MD and Omega:
Springans Merrymaker is literally a free Saryuja Skull Dread, and this deck has a comically easy time summoning two level 4 monsters. Springans Merrymaker should always activate its pitch effect, so that Tally-ho! Springans can always summon 3 and get you to Saryuja Skull Dread . If you are going first, nothing is higher priority than this other than Genta, Gateman of Dark World / The Gates of Dark World .
If you have an extra Genta, Gateman of Dark World in hand and The Gates of Dark World is on field (and you've already activated its effect) when you play Tally-ho! Springans , activate Springans Kitt on chain link 1 and Gigantic "Champion" Sargas on chain link 2, targeting The Gates of Dark World to bounce and then sending it back to deck with Springans Kitt .
Saryuja Skull Dread 's special summon effect can be hard to tell when to use, because we do ultimately want to Link him off for Apollousa, Bow of the Goddess , but I've found that doing it on any level 8 works perfectly fine.
Called by the Grave should probably be main deck but I'm a greedy bitch.
Lucent, Netherlord of Dark World can be interchanged with any of -goldd
When going second, make fusion summoning Grapha, Dragon Overlord of Dark World your top priority because he can turn an opponent's interaction into a massive advantage for you.
This deck fills up the board a lot, which is the primary function of both - and Knightmare Unicorn .
Recall that, because it discards as a cost rather than an effect, Knightmare Unicorn does not trigger our DW cards.
This deck would have Chaos Angel if I was not poor. It's so good and absurdly easy for this deck to bring out especially when going second.
Masquerade the Blazing Dragon is mostly in our extra so we can pitch any Fiend (which is all DW cards) using Branded in High Spirits .
Albion the Branded Dragon is at two copies so we can guaranteed use the secondary effect of Branded in High Spirits , since that secondary effect is the main reason we run the card.
Don't be overzealous in using the graveyard effects of Reign-Beaux, Overking of Dark World and Grapha, Dragon Lord of Dark World , it is very easy to end up with a hand full of shit and no ways left to get rid of it.
The Zombie Vampire may seem like an unremarkable inclusion, but if you take one of their monsters with either Snoww, Unlight of Dark World or Grapha, Dragon Lord of Dark World you can just keep their monster hostage underneath it by treating it as a Level 8 with The Zombie Vampire .
Pot of Avarice should always return as many Danger! monsters as possible, in particular Danger!? Jackalope? , Danger! Bigfoot! ,and Danger! Mothman!
Ceruli, Guru of Dark World is only good to add when you have other mechanisms of discarding (i.e. Danger! monsters, Branded in High Spirits )
Danger! Ogopogo! should always bin Danger! Chupacabra! since its a Fiend that you can banish with The Gates of Dark World
Danger! Nessie! is not good for this deck because we're doing lots of XYZ Summoning as opposed to normal Danger Dark World things, but a little Level/Rank 7 Package is included in the extra deck for those of you that just need Danger! Nessie! to play Danger Dark Worlds.